Thermosiphon with multiport tube and flow arrangement

ABSTRACT

A thermosiphon device includes one or more flat multiport tube structures having at least one section that defines a plurality of flow channels and at least one web that extends from the section in a plane of the flat multiport tube structures. The flow channels may function as condensing channels, e.g., in a counterflow device, or as evaporation channels. A multiport tube structure may include two sections that each define a plurality of flow channels and the two sections may be joined by a web that extends between the sections in the plane of the multiport tube structure. The sections may function as condensing channels, as evaporation channels, or one section may function as a set of evaporation channel and the other section may function as a set of condensing channels. Multiport tube sections may alternately function as a vapor supply path or liquid return path.

BACKGROUND OF THE INVENTION

1) Field of Invention

This invention relates generally to thermosiphon devices and other heattransfer devices that employ a two-phase fluid for cooling.

2) Description of Related Art

Thermosiphon devices are widely used for cooling systems, such asintegrated circuits and other computer circuitry. For example, U.S.Patent Publication 2013/0104592 discloses a thermosiphon cooler used tocool electronic components located in a cabinet or other enclosure.

SUMMARY OF THE INVENTION

One aspect of the invention provides a thermosiphon device including anevaporator section arranged to receive heat and evaporate a liquid, anda condenser section arranged to transfer heat from evaporated liquid toa surrounding environment to condense the evaporated liquid. At leastone flat multiport tube structure may be employed in the device andinclude one or more functional sections of the device, such asevaporator and condenser channels. For example, a flat multiport tubestructure may have a first section defining one or more flow channels, asecond section defining one or more flow channels, and a web thatextends between the first and second sections in a plane of themultiport tube structure. Thus, the web may connect the first and secondsections together while providing at least some degree of thermalisolation between the two. For example, the web may include one or moregaps (e.g., areas where the web is removed) to help limit thermaltransfer between the first and second sections, help reduce weight orcost, etc.

The thermal isolation and/or physical separation of the first and secondsections provided by the web may allow the sections to performdifferent, or the same, functions in the thermosiphon device. In someembodiments, the first section may define one or more evaporationchannels, and the second section may define one or more evaporationchannels, one or more condensing channels, or a liquid return path ofthe evaporator section. Alternately, or in addition, the first sectionmay define one or more condensing channels, and the second section maydefine one or more evaporation channels, one or more condensingchannels, or a vapor supply path of the condenser section. As a result,different functional portions of the thermosiphon device may be formedas part of a single multiport tube structure, helping to ease assembly,simplify device design, and/or enhance device operation. Where multipletube structures are used, the tube structures may provide a variety ofdifferent functions. Thus, the multiport tube structure may allow forgreater flexibility in design since various functional features can beincorporated into tube structure or structures used in the device.

In some devices, the evaporator section may include at least oneevaporation channel arranged to receive heat and evaporate a liquid inthe at least one evaporation channel and a liquid return path fordelivering condensed liquid to the at least one evaporation channel. Inone embodiment, the evaporation channels and liquid return path may becombined into a multiport tube structure, e.g., the at least oneevaporation channel and the liquid return path may be part of a flatmultiport tube structure in which the first section defines the at leastone evaporation channel and the second section defines the liquid returnpath. Similarly, a condenser section may include at least one condensingchannel arranged to transfer heat from evaporated liquid to asurrounding environment to condense the evaporated liquid and a vaporsupply path for delivering evaporated liquid to the at least onecondensing channel. The at least one condensing channel and the vaporsupply path may be part of a flat multiport tube structure in which thesecond section defines at least one condensing channel and the firstsection defines the vapor supply path. At least one manifold may fluidlyconnect the at least one evaporation channel with the vapor supply path,and fluidly connect the at least one condensing channel with the liquidreturn path. For example, a manifold may include an outer wall thatdefines an interior cavity and a separation wall positioned in theinterior cavity to separate the interior cavity into a vapor chamber anda liquid chamber. The separation wall may be positioned in the manifoldsuch that the at least one evaporation channel and the vapor supply pathare in fluid communication with the vapor chamber, and the at least onecondensing channel and the liquid return path are in fluid communicationwith the liquid chamber. Two or more multiport tube structures may beprovided as part of the evaporator or condenser section, e.g., toincrease a heat capacity of the system.

In another embodiment, a single multiport tube structure may defineportions of both the condenser and evaporator sections. For example, asingle flat multiport tube structure may have a first section thatdefines at least one evaporation channel and a vapor supply path, and asecond section that defines a liquid return path and at least onecondensing channel. As a result, a single tube structure may form acomplete thermosiphon device, and a plurality of such flat multiporttube structures may be provided in a thermosiphon device, if desired.

In some embodiments, a flat multiport tube structure may include one ormore lateral webs that extend outwardly from the first or second sectionin a plane of the flat multiport tube structure. The lateral web(s) mayprovide thermal transfer structure (e.g., exchange heat with asurrounding environment), or provide protection for portions of thethermosiphon device. In addition, or alternately, the flat multiporttube structure may include three or more sections that define flowchannels, and the sections may be connected such that adjacent sectionshave a web extending between the sections. This may allow a multiporttube structure to incorporate several different functional elements. Forexample, a first section of the multiport tube structure may define aplurality of condenser channels, the second section may define the vaporsupply path, and the third section may define a plurality of condenserchannels.

In another aspect of the invention, a thermosiphon device may includeone or more flat multiport tube structures having a first section thatdefines one or more flow channels, and a web that extends laterally awayfrom the first section in a plane of the multiport tube structure. Thefirst section may define a plurality of evaporation channels or aplurality of condenser channels. The web may be useful in defining aninsertion depth of an end of the first section into a manifold or otherstructure to which the multiport tube structure is fluidly coupled. Forexample, the web may act as a stop to define the insertion depth, whichmay be important to control or influence flow of liquid or vapor from orinto the first section. In one case, a liquid return path may need to bepositioned below a set of evaporation channels in a manifold to ensurethat liquid enters the liquid return path rather than the evaporationchannels. In such a case, the web on a multiport tube that defines theevaporation channels may cut or otherwise formed to define a gap thatsets a proper insertion depth of the first section into a manifold whenthe web contacts the manifold. In some cases, a multiport tube structuremay have first and second webs that extend laterally away from oppositesides of the first section in a plane of the multiport tube structure,e.g., to enlarge a heat transfer area. Multiport tube structures havingthis arrangement may be employed as part of the evaporator section,e.g., to provide evaporation channels, and/or as part of a condensersection, e.g., to provide condenser channels. When employed to providecondenser channels, the condenser section may operate in a counterflowmode (where vapor moves generally upwardly in the channels whilecondensed liquid travels generally downwardly) or in a loop mode (wherevapor and condensed liquid move generally in a same direction). Suchmultiport tube structures may also be used for other purposes, such asfluid connecting conduits or other pathways that are not designed orintended to transfer significant amounts of heat with respect to a fluidin the conduit.

These and other aspects of the invention will be apparent from thefollowing description. Also, it should be appreciated that differentaspects of the invention may be combined in a variety of different ways.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form a part ofthe specification, illustrate select embodiments of the presentinvention and, together with the description, serve to explain theprinciples of the inventions. In the drawings:

FIG. 1 is a perspective view of a thermosiphon device in an illustrativeembodiment that incorporates aspects of the invention;

FIG. 2 shows a thermosiphon device in another illustrative embodimenthaving a bent configuration;

FIG. 3 shows a close up view of the FIG. 2 embodiment;

FIG. 4 shows an illustrative embodiment of a multiport tube structurehaving a connecting web;

FIG. 5 shows a modified version of the FIG. 4 embodiment;

FIG. 6 shows an end view of a manifold coupled to condenser andevaporator sections including multiport tube structures;

FIG. 7 shows a perspective view of the manifold in FIG. 6;

FIG. 8 shows a separation wall in one embodiment;

FIG. 9 shows a separation wall in another embodiment;

FIG. 10 shows an end view of a manifold incorporating the separationwall of FIG. 8;

FIG. 11 shows a multiport tube structure having a connecting web andtooth;

FIG. 12 shows an end view of a manifold incorporating the separationwall of FIG. 9;

FIG. 13 shows a section of a manifold arranged to receive the multiporttube structure of FIG. 11;

FIG. 14 shows a separation wall in another embodiment that includes abarb or clip with a laterally extending element;

FIG. 15 shows an end view of a manifold incorporating the separationwall of FIG. 14;

FIG. 16 shows the manifold of FIG. 15 with the multiport tube structurespositioned for attachment to the manifold;

FIG. 17 shows the manifold of FIG. 16 with spacer elements in place;

FIG. 18 shows an end view of a manifold incorporating another separationwall embodiment;

FIGS. 19-22 show embodiments of a multiport tube structure incorporatingthermal transfer structure;

FIG. 23 shows an illustrative embodiment of a multiport tube structurehaving a three sections joined by connecting webs and having lateralwebs;

FIG. 24 shows a thermosiphon device incorporating the multiport tubestructure of FIG. 23;

FIG. 25 shows an end view of a manifold of the FIG. 24 embodiment alongwith a cap structure;

FIG. 26 shows the manifold of the FIG. 24 embodiment;

FIGS. 27 and 28 show an alternate end cap arrangement;

FIG. 29 shows a thermosiphon device in which a multiport tube structuredefines portions of both an evaporator and condenser section;

FIG. 30 shows a thermosiphon device similar to that of FIG. 29 buthaving a bent configuration;

FIG. 31 shows a multiport tube structure for use in the FIGS. 29 and 30embodiments;

FIG. 32 shows a thermosiphon device like that of FIG. 30 and havingmultiple multiport tube structures;

FIG. 33 shows a manifold of the FIG. 32 embodiment;

FIG. 34 shows a modified version of the device of FIG. 29 that omitsconduits between manifolds;

FIG. 35 shows a manifold arrangement for the embodiment of FIG. 34;

FIG. 36 shows a thermosiphon device including multiport tube structuresof the condensing section arranged for counterflow operation;

FIG. 37 shows a side view of the device of FIG. 36;

FIG. 38 shows a multiport tube structure for use in the FIG. 36embodiment;

FIG. 39 shows the manifold and a multiport tube structure of the FIG. 36embodiment;

FIG. 40 shows a multiport tube structure having lateral webs flush witha surface of the channel section;

FIG. 41 shows a multiport tube structure having lateral webs with a bentportion;

FIG. 42 shows a multiport tube structures having thermal transferstructure arranged between the structures;

FIG. 43 shows a multiport tube structure having gaps in the webs at anend of the structure;

FIG. 44 shows a thermosiphon device in which a multiport tube structureshown in FIG. 43;

FIG. 45 shows a thermosiphon device similar to that of FIG. 45 butomitting a lower turnaround;

FIG. 46 shows a side view of the device of FIG. 45;

FIG. 47 shows a thermosiphon device in which multiport tube structuresdefine portions of both the evaporator and condenser sections;

FIG. 48 shows a thermal transfer structure arrangement for use in theFIG. 47 device;

FIG. 49 shows a modified version of the FIG. 47 device in which an upperturnaround manifold is replaced with bent tube sections;

FIG. 50 shows a modified version of the FIG. 49 device in which a lowerturnaround manifold is replaced with bent tube sections;

FIG. 51 shows a thermosiphon device in which multiport tube structuresdefine a condenser section;

FIG. 52 shows a side view of the FIG. 51 embodiment;

FIG. 53 shows the evaporator section and vapor supply path of the FIG.51 device;

FIG. 54 shows a manifold of the FIG. 51 device;

FIG. 55 shows a multiport tube structure including the condenserchannels of the FIG. 51 device;

FIG. 56 shows a base plate for the FIG. 51 device;

FIG. 57 shows a thermosiphon device similar to the FIG. 51 device butoriented in a vertical direction;

FIG. 58 shows a thermosiphon device having multiple devices like thatshown in FIG. 57;

FIG. 59 shows a thermosiphon device similar to the FIG. 58 device andhaving a turnaround for the evaporator section;

FIG. 59A shows a thermosiphon device similar to the FIG. 59 device andhas condenser section manifolds coupled in fluid communication;

FIG. 60 shows a thermosiphon device including counterflow condenserchannels and an evaporator section including a turnaround;

FIG. 61 shows a thermosiphon device in which multiport tube structuresinclude condensing and evaporation channels;

FIG. 62 shows the FIG. 61 device with manifolds removed;

FIG. 63 shows a multiport tube structure for use in the FIG. 61 device;

FIG. 64 shows a thermosiphon device similar to the device of FIG. 61 andhaving only evaporator and condenser channel of each multiport tubestructure fluidly connected;

FIG. 65 shows a multiport tube structure for use in the FIG. 64 device;

FIG. 66 shows a thermosiphon device including counterflow condenserchannels arranged in a multiport tube structure;

FIG. 67 shows a multiport tube structure for use in the FIG. 66 device;

FIG. 68 shows the FIG. 66 device in a vertical orientation;

FIG. 69 shows a manifold arrangement including plugs to control liquidflow;

FIG. 70 shows a modified version of the FIG. 66 device with condensingchannels arranged at a non-perpendicular angle to a plane of themanifold;

FIG. 71 shows the FIG. 70 device in a vertical orientation;

FIG. 72 shows a base plate for the FIG. 66 device;

FIG. 73 shows a thermosiphon device including counterflow condenserchannels arranged in a multiport tube structure and a multipartmanifold;

FIG. 74 shows a multiport tube structure for use in the FIG. 73 device;

FIG. 75 shows a manifold sheet for the FIG. 73 device;

FIG. 76 shows the FIG. 73 device in a vertical orientation;

FIG. 77 shows the FIG. 73 device in an alternate vertical orientation;

FIG. 78 shows an alternate manifold structure for the FIG. 73 device;

FIG. 79 shows a base plate for the FIG. 78 device;

FIG. 80 shows an alternate manifold arrangement for the FIG. 73 device;

FIG. 81 shows a modified version of the FIG. 66 device with manifoldsattached via a multiport tube conduit;

FIG. 82 shows a close up view of a portion of the FIG. 81 device;

FIG. 83 shows a multiport tube conduit for use in the FIG. 81 device;

FIG. 84 shows a close up view of a multiport tube conduit engagementwith manifolds in the FIG. 81 device;

FIG. 85 shows an alternate liquid trapping arrangement includinginternal threads;

FIG. 86 shows a coil element for use in liquid trapping in a manifold;

FIG. 87 shows a thermosiphon device having multiple, vertically orientedmultiport tube structures including counterflow condenser channels;

FIG. 88 shows a circular manifold of the FIG. 87 device;

FIG. 89 shows a plug for use in the manifold of the FIG. 87 device;

FIG. 90 shows an alternate manifold arrangement for the FIG. 87 deviceincluding a wicking element;

FIG. 91 shows a thermosiphon device similar to the FIG. 87 device andhaving a manifold with a cylindrical chamber;

FIG. 92 shows an alternate manifold arrangement for the FIG. 91 deviceincluding a wicking element;

FIG. 93 shows alternate manifold arrangement for the FIG. 87 deviceincluding a plurality of cavities in the manifold bottom wall;

FIG. 94 shows a thermosiphon device with multiple, vertically orientedmultiport tube structures including counterflow condenser channels and aserpentine manifold; and

FIG. 95 shows the FIG. 94 device in a vertical orientation;

DETAILED DESCRIPTION

Aspects of the invention are not limited in application to the detailsof construction and the arrangement of components set forth in thefollowing description or illustrated in the drawings. Other embodimentsmay be employed and aspects of the invention may be practiced or becarried out in various ways. Also, aspects of the invention may be usedalone or in any suitable combination with each other. Thus, thephraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting.

FIG. 1 shows an illustrative embodiment of a thermosiphon device 10,e.g., used to cool electronics devices in a closed cabinet or otherenclosure 6. That is, as is understood by those of skill in the art, oneor more evaporator sections 2 of the device 10 may be positioned in asealed enclosure 6 along with electronics or other heat-generatingdevices to be cooled. One or more condensing sections 1 may bepositioned outside of the sealed enclosure 6 and dissipate heat receivedfrom the evaporator section(s) 2, e.g., to air in an environment outsideof the sealed enclosure 6. A flange 33 on a manifold 3 or elsewhere inthe device 10 may be engaged with an opening of the sealed enclosure,thereby sealing the enclosure 6 and defining a dividing point betweenportions inside of the enclosure 6 and an environment outside of theenclosure. By providing the evaporator section(s) 2 inside the sealedenclosure 6 and the condenser section(s) 1 outside of the enclosure 6,devices in the enclosure 6 may be cooled while being contained in anenvironment protected from external conditions, e.g., protected fromdirt, dust, contaminants, moisture, etc. Of course, use of athermosiphon device with a sealed enclosure is not required, e.g., thedevice may be used in a completely open system in which heat generatingdevices to be cooled are thermally coupled to one or more evaporatorsection(s) 2 of the device 10. Also, the embodiment of FIG. 1 shows thethermosiphon device 10 arranged at a relatively shallow angle to thehorizontal, but the device 10 may be oriented in different ways, e.g.,vertically or other angles to the horizontal, and may be arranged tooperate in a variety of different positions as discussed in more detailbelow. Also, the device 10 need not be flat as in FIG. 1, but may bearranged in a bent configuration such as shown in FIG. 2 or in otherways.

FIG. 3 shows a close up view of a portion of the thermosiphon device 10of FIG. 2. In simplified form, the thermosiphon device 10 operates tocool heat generating devices by receiving heat at the evaporatorsection(s) 2 such that liquid in evaporation channels 22 boils orotherwise vaporizes. Heat may be received at the evaporation channels 22by warm air (heated by the heat generating devices) flowing across athermal transfer structure 23 that is thermally coupled to theevaporation channels 22 or in other ways, such as by a direct conductivepath, one or more heat pipes, a liquid heat exchanger, etc. Vapor flowsupwardly from the evaporation channels 22 into a manifold 3, and theninto a vapor supply path 11 of a condenser section 1. The vaporcontinues to flow upwardly in the vapor supply path 11 until reaching aturnaround 14 (see FIG. 2) of the condenser section 1. At this point,the vapor flows downwardly into one or more condensing channels 12 ofthe condenser section 1, where the vapor condenses to a liquid and flowsdownwardly into the manifold 3. Heat removed from the vapor duringcondensation may be transferred to thermal transfer structure 13 coupledto the condensing channels 12, e.g., one or more fins conductivelycoupled to the condenser section 1 adjacent the condensing channels 12.In turn, heat may be removed from the thermal transfer structure 13 bycool air flowing across the structure 13, by a liquid bath, a liquidheat exchanger, refrigerant coils, or other arrangement. The condensedliquid flows downwardly from the condensing channels 12 into themanifold 3 and then into a liquid return path 21 of an evaporatorsection 2 until reaching a turnaround 24 (see FIG. 2) of the evaporatorsection 2. The liquid then enters an evaporator channel 22 and theprocess is repeated.

In accordance with an aspect of the invention, the condenser section 1and/or evaporator section 2 may be arranged as a flat multiport tubestructure in which functionally different channel sections are attachedto each other by a flat web that extends between the channel sections inthe plane of the multiport tube structure. For example, the evaporatorsection may include one or more flat multiport tube structures that eachhave at least one evaporation channel section joined to a liquid returnpath section by a flat web that extends in a plane of the multiport tubestructure. Alternately, or in addition, the condenser section mayinclude one or more flat multiport tube structures that each have atleast one condensing channel section joined to a vapor supply pathsection by a flat web that extends in a plane of the multiport tubestructure. By having the different sections joined by a flat web, heattransfer between the sections may be minimized, particularly if the webis made very thin, discontinuous and/or of a material having arelatively low thermal conductivity. Reduced heat transfer may provideadvantages, such as helping to ensure proper thermal performance of thethermosiphon device 10 and suitable vapor and liquid flow. For example,reduced heat transfer between a liquid return path section and anevaporation channel section may help maintain working fluid in liquidform in the liquid return path, thereby helping ensure proper flowcirculation in the thermosiphon device. Similar is true for thecondensing channel section and the vapor supply path, i.e., reduced heattransfer may help maintain working fluid in vapor form in the vaporsupply path. Moreover, by combining different functional sections of theevaporator and/or condenser sections into a single part, manufacture andassembly can be simplified.

FIGS. 4 and 5 show illustrative embodiments of a flat multiport tubestructure that may be employed as part of an evaporator or condensersection in accordance with aspects of the invention. In FIG. 4, themultiport tube 100 includes a first section 101 and a second section 102that are joined by a flat web 103 that extends between the sections 101,102 in a plane of the multiport tube 100. The first section 101 in thisembodiment includes multiple flow channels, and could function as a setof evaporation channels 22 or condensing channels 12 or other flowconduit. The second section 102 includes a single channel, and couldfunction as a liquid return path 21 or vapor supply path 11 or otherflow conduit. Of course, it will be understood that any suitable numberof channels may be employed in the first and/or second sections 101,102. The web 103 may have any suitable width, thickness and/or length,and may be made of any suitable material, which may be different thanthe material used to form the first and/or second sections 101, 102. Forexample, a wider and/or thinner web 103 may help reduce heat transferbetween the first and second sections 101, 102. As another example,portions of the web 103 may be removed, e.g., punched out, to provide agap between the first and second sections 101, 102 while stillmaintaining a mechanical connection between the sections 101, 102. FIG.5 shows an arrangement in which a gap 104 is provided by removal of aportion of the web 103. While in the FIG. 5 embodiment a portion of theweb 103 at an end of the multiport tube 100 is removed, other portionsof the web 103 may be removed, such as portions positioned anywherealong a length of the web 103. Thus, one or more gaps 104 may beprovided in the web 103, whether to reduce weight, help control heattransfer, reduce cost, and/or other purposes. Also, as discussed morebelow, a web 103 is not limited to a single flat element that extendsbetween the first and second sections 101, 102 at a center point in thethickness dimension of the multiport tube structure 100 as shown inFIGS. 4 and 5. Instead, for example, the web 103 may be positioned so asto be flush with one or both side surfaces of the first and secondsections 101, 102, e.g., so that the first and second sections 101, 102and the web 103 define a continuous flat, planar surface. Also, two ormore webs 103 may be provided, if desired, e.g., with one web 103positioned flush with a top side surface of the first and secondsections 101, 102 and another web 103 positioned flush with a bottomside surface of the first and second sections 101, 102. Where two ormore webs 103 are provided and if the webs 103 define a potential flowchannel, the flow channel is not employed by the device 10, e.g., theflow channel may contain only air, insulation or other material that isnot working fluid for the device 10. An arrangement in which themultiport tube structure 100 includes webs 103 positioned flush at bothside surfaces of the first and second sections 101, 102 may beconvenient for manufacture, e.g., because the multiport tube structure100 may initially be made as a conventional multiport tube, and aportion of the tube that defines one or more flow channels may bearranged to function as the web 103 section, e.g., portions of the tubeat the web section may be notched, removed, otherwise altered or simplynot employed as a flow channel for the device. Moreover, the web(s) 103need not be completely flat as shown, but may be corrugated, have asurface texture or be arranged in other ways.

In accordance with another aspect of the invention, providing a gap 104in a web 103 near an end of a multiport tube 100 may also help define arelationship between the multiport tube 100 and a manifold 3 or otherstructure to which the multiport tube 100 is attached. For example, FIG.6 shows an illustrative embodiment of a device 10 that includes acondenser section 1 and an evaporator section 2 that include a multiporttube like that shown in FIG. 5. The manifold ends of the multiport tubestructure of the condenser and evaporator sections 1, 2 are insertedinto openings of the outer wall of the manifold 3 so that the gap 104 ispositioned in the manifold 3. A separation wall 35 in the manifold 3divides the internal space of the manifold 3 into a vapor chamber 32 anda liquid chamber 31, and ends of the separation wall 35 extend into thegaps 104 of the multiport tubes 100. As a result, the evaporationchannels 22 and the vapor supply path 11 are fluidly connected to thevapor chamber 32, and the condensing channels 12 and the liquid returnpath 21 are fluidly connected to the liquid chamber 31. FIG. 7 shows aperspective view of the manifold 3 without the condenser and evaporatorsections 1, 2 engaged with the manifold 3. As can be seen, the outerwall 34 of the manifold 3 has openings 331, 332, 333, 334 to receiveportions of the manifold end of the condenser and evaporator sections 1,2. That is, the openings 331 are arranged to receive a first section 101of a multiport tube 100 that defines the condensing channels 12, theopenings 332 are arranged to receive a second section 102 of a multiporttube 100 that defines the vapor supply path 11, the openings 333 arearranged to receive a first section 101 of a multiport tube 100 thatdefines the evaporation channels 22, and the openings 334 are arrangedto receive a second section 102 of a multiport tube 100 that defines theliquid return path 21. The openings 331 and 332 for each multiport tube100 are separated by a solid portion of the outer wall 34 which contactsa leading end of the web 103 of each multiport tube 100 so as to limitthe extent to which the manifold end of the multiport tube 100 can beinserted into the manifold 3. Thus, the insertion depth of eachmultiport tube structure 100 can be relatively easily defined byestablishing a desired length for the gap 104, i.e., the multiport tube100 can be inserted into the manifold 3 until the web 103 contacts theouter wall 43 of the manifold 3.

While the separation wall 35 in the FIGS. 6 and 7 embodiment is arrangedas a plate having an S shape with straight ends, the separation wall 35can be arranged in other ways. For example, FIG. 8 shows a separationwall 35 that includes a folded barb or hairpin clip 351 at ends of thewall 35. FIG. 9 shows another separation wall 35 that includes a foldedbarb or hairpin clip 351 at ends of the wall 35, but the wall 35 in thiscase has a different overall shape, e.g., a lazy Z shape. Of course,other shapes for a separation wall 35 are possible. FIG. 10 shows anembodiment similar to that in FIGS. 6 and 7, but employing a separationwall 35 like that in FIG. 8. As can be seen, the barb or clip 351 atends of the wall 35 engage with the multiport tube structures 100 at thegap 104 so that the multiport tube structures 100 are held in place byfriction with the barb or clip 351. This may help hold the multiporttube structures 100 in place in preparation for brazing or other processto securely join the multiport tube structures 100 with the manifold 3.

In another aspect of the invention, a multiport tube structure 100 mayinclude a tooth or other engagement feature to help secure the multiporttube structure 100 in place with respect to a manifold 3 or otherelement. For example, FIG. 11 shows an illustrative embodiment thatincludes a tooth 105 formed in the gap 104 at the manifold end of amultiport tube structure 100. In this case, the tooth 105 is formed byremoving a section of the web 103 to form both the gap 104 and the tooth105, but other arrangements are possible, such as welding or otherwiseattaching a tooth, barb, tab or other engagement element to themultiport tube structure 100. As can be seen in FIG. 12, the tooth 105may engage a portion of a separation wall 35 or other component so thatthe manifold end of the multiport tube structure 100 is captured inengagement with the manifold 3 or other component. In this embodiment,the separation wall 35 is arranged like that shown in FIG. 9, and adistal end of the hairpin clip 351 is captured on a proximal side of thetooth 105 so that the multiport tube structure 100 is held in place. Asa result, the manifold end of each multiport tube structure 100 may beinserted into the manifold 3 until the clip 351 is captured at theproximal end of the tooth 105, ensuring the multiport tube structure 100is properly positioned in the manifold 3. As can be seen in FIG. 13,openings 331 in the manifold 3 may be arranged to receive the tooth 105,e.g., to have a relatively small slit extending from the main opening331 to allow the tooth 105 to pass through.

As noted above, the separation wall 35 and clips or barbs 351 may bearranged in other ways. FIG. 14 shows another illustrative embodiment inwhich the clips or barbs 351 include a laterally extending portion at adistal end. As can be seen in FIG. 15, a tooth 105 and gap 104 of amultiport tube 100 may be arranged so that the laterally extendingportion of the clip or barb 351 is captured on a proximal side of thetooth 105, thereby latching the multiport tube structure 100 inengagement with the manifold 3. As also shown in this embodiment, thegap 104 is made relatively long so that the web 13 does not contact theouter wall 34 of the manifold 3 when the multiport tube structure 100 isproperly positioned relative to the manifold 3 with the laterallyextending portion of the clip or barb 351 in contact with the tooth 105.Instead, the gap 104 is sized so that jig or spacer elements 106 can bereceived into the gap 104 at a location outside of the manifold innerspace, as can be seen in FIGS. 16 and 17. The spacer elements 106 inthis embodiment are arranged as rectangular bars that may be arranged todefine the position of multiple multiport tube structures 100 relativeto a manifold 3. After brazing or other attachment of the multiport tubestructures 100 to the manifold 3 is complete, the spacer elements 106may be removed, or the elements 106 may be secured in place as well.

FIG. 18 shows another arrangement for a separation wall 35 that in thisembodiment is made of two parts 35 a, 35 b that are joined together. Oneor more openings 35 c may be provided in the separation wall 35, e.g.,along a section where the parts 35 a, 35 b are joined together, so thatliquid or vapor (in this case liquid) may pass from the condensersection 1 to the evaporator section 2.

As mentioned above, a multiport tube structure 100 may have thermaltransfer structure, such as fins, pins, studs or other structure to aidin heat transfer between a portion of the multiport tube structure 100and a surrounding environment. For example, FIG. 19 shows a crosssectional view of a multiport tube structure 100 that includes first andsecond sections 101, 102 joined by a web 103. Here again, the web 103 isshown extending between first and second sections 101, 102 at a midpointof a thickness of the first and second sections 101, 102, but such anarrangement is not required. Instead, the web 103 may be positioned ateither side surface of the first and second sections 101, 102, may havea thickness equal to the first and second sections 101, 102, may extendat an angle relative to the plane of the multiport tube structure 100(e.g., so as to extend the thermal pathway of the web 103 while notincreasing an overall width of the structure 100), may be corrugated orhave another non-flat shape, and others. Thermal transfer structure,such as fins 13, 23, are in thermal contact with the second section 102,which may function as condensing channels 12 or evaporating channels 22.So as to reduce heat transfer with respect to the first section 101, thethermal transfer structure 13, 23 stops short of, and does not contact,the first section 101. FIG. 20 shows a similar arrangement, except thatthe first section 101 is made thinner than the second section 102, or atleast has a surface nearest the thermal transfer structure 12, 23 thatis offset from the plane of the surface of the second section 102 towhich the thermal transfer structure is attached. This way, a gap ispresent between the thermal transfer structure 13, 23 and the firstsection 101, allowing the thermal transfer structure 13, 23 to have alarger size and yet still avoid contact with the first section 101. FIG.21 shows an arrangement similar to FIG. 19 except that the multiporttube structure 100 includes a flat web 107 that extends outwardly fromthe second section 102 in a plane of the multiport tube structure 100.This web 107 may serve as thermal transfer structure, e.g., a fin totransfer heat with respect to a surrounding environment, and/or may helpprotect the thermal transfer structure 13, 23. That is, the thermaltransfer structure 13, 23 may be relatively fragile such that portionsof the thermal transfer structure 13, 23 can be bent or otherwisedamaged with contact. The web 107 may help prevent such contact. FIG. 22shows another arrangement similar to FIG. 21, except that the multiporttube 100 includes a pair of flat webs 107 that extend away from thesecond section 102 in a plane of the multiport tube 100. In thisembodiment, the webs 107 are positioned so as to be flush with arespective side surface of the first and second sections 101, 102, butcould be arranged in other ways. Also, the thermal transfer structure13, 23 may be thermally connected to one of the flat webs 107, which mayaid in thermal transfer.

While in the embodiments above, the multiport tubes 100 included onlyfirst and second sections 101, 102 arranged to carry fluid, embodimentsare not limited in this regard. For example, FIG. 23 shows a multiporttube structure 100 that includes second and third sections 102, 108 thatare joined to a first section 101 by respective webs 103. As notedabove, such an arrangement may be useful where at least some degree ofthermal isolation between the first section 101 and the second and thirdsections 102, 108 is desired. It should also be understood that eachsection 101, 102, 108 may include any suitable number of channels, e.g.,1, 2, 3, 5, 10, 20, etc. This embodiment also includes flat webs 107that extend outwardly from the second and third sections 102, 108. Thesewebs 107 may aid in thermal transfer, provide strength and/or performother functions.

FIG. 24 shows an illustrative embodiment that employs a multiport tubestructure 100 like that in FIG. 23 in the condenser section 1. In thisexample, the first section 101 of the multiport tube structure 100functions as a vapor supply path 11 and provides working vapor to aturnaround 14 (which may be a tubular manifold that connects to multiplemultiport tube structures 100). The vapor is then distributed to thesecond and third sections 102, 108 which function as condensing channels12. Condensed working fluid, i.e., liquid, passes downwardly into liquidchambers 31 of the manifold 3 and to a liquid return path 21 of theevaporator section 2. The liquid is delivered to a turnaround 24 (whichmay be a tubular manifold that connects to multiple evaporation channels22 and liquid return paths 21), which supplies evaporator channels 22with working fluid in liquid form. Heat received by the working fluidevaporates the liquid, and the vapor travels upwardly to a vapor chamber32 of the manifold and to the first section 101. The evaporationchannels 22 and liquid return path 21 may be arranged in any suitableway, e.g., may include one or more multiport tube structures like thatin FIG. 5, a single flow channel conduit, etc.

FIG. 25 shows a close up view of the manifold 3 of the FIG. 24embodiment. As described above, the internal space of the manifold 3 isdivided into three chambers, i.e., a vapor chamber 32 and two liquidchambers 31. Since in this embodiment the liquid return path 21 isconnected only to the liquid chamber 31 on the right in FIG. 25, someprovision must be made to fluidly connect the two liquid chambers 31. Inaccordance with an aspect of the invention, the manifold includes an endcap 5 that includes an inner plate 54 with first and second openings 55and an outer plate 56. The inner plate 54 is attached inside themanifold 3 so as to sealingly engage the ends of the separation walls 35and the inner side of the manifold outer wall 34 so as to isolate thevapor chamber 32 from the liquid chambers 31. The outer plate 56 is thenattached to the end of the outer wall 34 of the manifold 3. Since theinner plate 54 is inset from the end of the manifold 3, a space isprovided between the outer plate 56 and the inner plate 54 so that theopenings 55 are fluidly connected to each other, thereby fluidlyconnecting the liquid chambers 31. In embodiments where a liquid returnpath 21 is connected to both liquid chambers 31, the openings 55 may beeliminated. In such a case, a relatively small opening may be providedin the inner plate 54 to allow fluid communication between the vaporchamber 32 and the space between the outer plate 56 and the inner plate54. This opening allows for equalization of pressure in the spacebetween the outer plate 56 and the inner plate 54 and the vapor chamber32, which can help prevent bowing of the inner plate 54 due to pressurein the vapor chamber 32. This can help ensure the inner plate 54maintains a suitable seal with the separation wall(s) 35.

FIG. 26 shows a close up view of the manifold in the FIG. 24 embodiment.The separation walls 35 are inset from the end of the outer wall 34 ofthe manifold 3 by a distance that approximately defines the offsetbetween the inner and outer plates 54, 56. That is, the inner plate 54fits inside of the outer wall 34 and contacts the ends of the separationplates 35 so that the inner plate 54 is inset relative to the end of theouter wall 34. Thus, when the outer plate 56 is attached to the end ofthe outer wall 34, the outer plate 56 is separated from the inner plate54 so that a chamber is defined between the inner and outer plates 54,56. This chamber provides the fluid communication between the openings55. The manifold is also shown as having openings 331, 332, 333, 334.Much like in the FIG. 7 embodiment, these openings respectively receivethe first section 101 and second and third sections 102, 108 of thecondenser section 1, the liquid return path 21 and the evaporationchannels 22.

FIGS. 27 and 28 show an alternate embodiment for an end cap 5. In anembodiment where the separation wall(s) 35 in a manifold 3 extend so asto be flush with the end of the outer wall 34 of the manifold 3, the endcap 5 may be arranged differently from that described above.Specifically, if the separation wall(s) 35 are not inset from the end ofthe outer wall 34, the end cap 5 may be arranged to provide a flow pathbetween the openings 55. In the illustrative embodiment of FIGS. 27 and28, the inner plate 54 has a larger diameter than in the aboveembodiment (e.g., equal or greater than the diameter of the manifold 3),and the outer plate is arranged to include a cylindrical wall element 56and a flat plate 57. As can be seen in FIG. 28, the inner plate 54 maybe attached to the cylindrical wall element 56 so that the inner plate54 is spaced from the flat plate 57. The inner plate 54 can then beattached to the ends of the outer wall 34 and the separation wall(s) 35to close the manifold 3. In an embodiment where the openings 55 areeliminated, the inner plate 54 may have a small opening to allow fluidcommunication between the vapor chamber 32 and the space between theflat plate 57 and the inner plate 54, as discussed above.

In another illustrative embodiment, both a condenser section and anevaporator section may be made from a single multiport tube structure.Moreover, the condenser section may include a vapor supply path separatefrom one or more condensing channels, and the evaporator section mayinclude a liquid return path that is separate from one or moreevaporation channels. For example, FIG. 29 shows a thermosiphon device10 that includes a multiport tube structure 100 that defines thecondenser section 1 and the evaporator section 2. FIG. 30 showsessentially the same arrangement except that the multiport tubestructure 100 is bent to form an angled device 10. FIG. 31 shows aperspective view of a multiport tube structure 100 that may be used toform the devices 10 in FIGS. 29 and 30. The first section 101 includesthree channels in this embodiment and may form the vapor supply path 11and the evaporator section 22. The second section 102 includes fivechannels in this embodiment and may form the condensing channels 12 andthe liquid return path 21. Of course, other numbers of channels may beused as desired. The first and second sections 101, 102 are joined by aweb 103 that extends in a plane of the multiport tube structure 100, andmay be solid, include one or more gaps 104 (not shown) along its length,etc. As can be seen in FIGS. 29 and 30, thermal transfer structure 13,23 is thermally coupled to portions of the first section 101 thatdefines the evaporation channels 22 and to portions of the secondsection 102 that defines the condensing channels 12. As described above,the thermal transfer structure 13, 23 may enhance heat transfer for thesections to which the structure 13, 23 is thermally coupled. Themultiport tube structure 100 may include outer webs 107 that extendoutwardly in the plane of the multiport tube structure 100 from thefirst and second sections 101, 102. These webs 107 may help transferheat and/or provide protection for the thermal transfer structure 13,23. The web 107 shown on the left in FIG. 31 includes a bumper section107 a that extends in a thickness direction of the multiport tubestructure 100 and may help protect thermal transfer structure 13, 23. Ofcourse, the webs 107 may be eliminated, altered in size and/or thicknessand/or material, notched or selectively removed in sections, etc.

At opposite ends of the multiport tube structure 100, the first andsecond sections 101, 102 are fluidly coupled by turnarounds that aredefined by manifolds 141, 142 for the condenser section 1 and manifolds241, 242 for the evaporator section 2. The manifolds 141, 142 and 241,242 may be fluidly coupled to each other by one or more conduits 143 sothat vapor or liquid can pass.

FIG. 32 shows a perspective view of a thermosiphon device 10 arrangedlike that in FIG. 30, but has a plurality of multiport tube structures100 arranged in parallel and communicating with the manifolds 141, 142and 241, 242. Thermal transfer structure 23 may be thermally coupled toadjacent pairs of evaporation channels 22 and may be arranged to allowfor air or other fluid flow between the multiport tube structures 100.Thermal transfer structure 13 may be similarly arranged for thecondenser section 1, but cannot be seen in FIG. 32.

FIG. 33 shows one of the manifolds 141 of the FIG. 32 embodiment andillustrates how the manifold 141 may include a plurality of openings 143to receive a manifold end of a multiport tube structure 100, andopenings 144 that connect to a conduit 143 (such as a pipe) thatprovides fluid coupling between the manifold 141 and the manifold 142.The other manifolds 142, 241 and 242 may be similarly arranged.

FIG. 34 shows an arrangement similar to that in FIG. 29, except thatconduits 143 that provide fluid coupling between the manifolds 141, 142and 241, 242 are eliminated. Instead, the manifolds 141, 142 and 241,242 are butted up against each other so that the manifolds 141, 142 and241, 242 may communicate directly through the openings 144. FIG. 35illustrates how the manifolds 141, 142 may be joined together such thatthe openings 144 in each manifold are aligned to provide fluidcommunication between the manifolds 141, 142. While the embodiment ofFIG. 34 has a flat or planar arrangement, the manifold arrangement maybe employed in a bent configuration like that in FIG. 30 or other device10 configurations. Of course, one potential benefit of the arrangementin FIG. 29 as compared to the FIG. 34 embodiment is that the vaporconducting portions (the evaporation channels 22 and vapor supply path11) may be further distanced from, and better thermally separated from,the liquid conducting portions (the condensing channels 12 and liquidreturn path 21).

In accordance with another aspect of the invention, a thermosiphondevice may have an evaporator section or condenser section that includesa flat multiport tube structure having a section defining a plurality ofadjacent flow channels and one or more flat webs that extend away fromthe flow channels in a plane of the multiport tube structure. Forexample, FIGS. 36 and 37 show a thermosiphon device 10 that has aplurality of multiport tube structures 100 that form the condensersection 1 and a plurality of multiport tube structures 100 that defineevaporation channels 22 for the evaporator section 2. The multiport tubestructures 100 may have an arrangement like that shown in FIG. 38 inwhich a first section 101 includes one or more flow channels, e.g., todefine condensing channels or evaporation channels, and one or more flatwebs 107 that extend outwardly from the flow channels in a plane of themultiport tube structure 100. The webs 107 may function as thermaltransfer structure, e.g., to transfer heat with respect to working fluidin the flow channels. The multiport tube structures 100 of the condensersection 1 may each have a manifold end fluidly coupled with a manifold3, e.g., to receive working fluid vapor and deliver condensed workingfluid liquid. An upper end of the multiport tube structures 100 may befluidly coupled to a turnaround 14, such as a tubular manifold. Themultiport tube structures 100 of the evaporator section 2 in thisembodiment are rotated 90 degrees about a vertical axis relative to themultiport tube structures 100 of the condenser section 1 and also have amanifold end fluidly coupled to the manifold 3, e.g., to deliver workingfluid vapor to the manifold 3. The webs 107 of the multiport tubestructures 100 of the evaporator section 2, along with a surface of thefirst section 101, may provide a surface to which heat generatingcomponents such as electronic devices, can be mounted so that heat canbe transferred to the webs 107, and thus to the working fluid in theevaporation channels 22. In this embodiment, a pair of liquid returnpath conduits 21 fluidly couple the manifold 3 and a turnaround 24(e.g., a tubular manifold) so that condensed working fluid is deliveredto the turnaround 24 and thus to the evaporation channels 22. The liquidreturn path conduits 21 may be arranged as a multiport tube structure100 as well, or may be single lumen conduit with no web. In thisembodiment, the condensing channels 12 operate as a counterflow devicein which vapor travels upwardly through the condensing channels 12 whilecondensed liquid travels downwardly in the condensing channels 12.However, a dedicated vapor supply path could be provided, if desired,e.g., in a way similar to embodiments described above or otherwise.

One advantage to using a multiport tube structure 100 for the evaporatorand/or condenser sections 2, 1 is that the web(s) 107 may be used todefine an insertion depth of the multiport tube structure 100 withrespect to a manifold. For example, FIG. 39 shows the manifold 3 of theFIG. 36 embodiment with a plurality of openings 331 to receive the firstsection 101 of a respective multiport tube structure 100. While thefirst section 101 is received into the opening 331, one or more webs 107of the multiport tube structure 100 may contact the outer wall 34 of themanifold 3 and function as a stop to define the insertion depth of thefirst section 101 into the manifold 3. This function can be particularlyuseful when assembling a thermosiphon device 10 and ensuring thatcertain portions of the device 10, such as a set of evaporation channels22, are inserted further into a manifold 3 than other portions of thedevice 10, such as a liquid return path 21. This relative relationshipof the evaporation channels 22 and liquid return path 21 can be seen inFIG. 37 and helps ensure that liquid flows downwardly into the liquidreturn path 21 rather than the evaporation channels 22. As a result,assembly of the device 10 can be simplified since the multiport tubestructures 100 may be inserted into a manifold until a stop is contactedand then secured in position.

While FIG. 38 shows one illustrative embodiment for a multiport tubestructure 100 and outer web arrangement, other arrangements arepossible. For example, FIG. 40 shows another configuration in which apair of webs 107 are positioned so as to be flush with one side surfaceof the first section 101. Such a configuration may be useful, forexample, when attaching a heat generating component, heat plate or otherstructure to the multiport tube structure 100. Other arrangements arepossible too, including a multiport tube structure 100 with webs 107extending from both side surfaces of the first section 101, etc. FIG. 41shows another arrangement in which webs 107 have portions that extendoutwardly from the first section 101 in the plane of the first section101, and have upwardly extending portions arranged perpendicular to theplane of the multiport tube structure 100. Such an arrangement mayincrease the surface area of the webs 107 while reducing the overallwidth of the multiport tube structure 100, and could be used for theevaporation channels 22 in the FIG. 36 embodiment. FIG. 42 shows yetanother arrangement for a multiport tube structure 100 in which the webs107 have a thickness equal to the first section 101. Thus, the webs 107are flush with both side surfaces of the first section 101. Onepossibility for such an arrangement is to provide thermal transferstructure 13, 23, such as one or more fins, that are thermally coupledto the webs 107 and first sections 101 of adjacent multiport tubestructures 100. FIG. 43 shows yet another arrangement in which webs 107define a gap 104 near an end of the first section 101. As can beappreciated in FIG. 44, the gaps 104 may help define an insertiondistance for the first section 101 into a manifold 3 while theadditional surface area of the webs 107 may aid in heat transfer.

While the arrangement in FIG. 44 shows the liquid return path 21 andevaporation channels 22 in communication with a turnaround 24, otherarrangements are possible such as that shown in FIGS. 45 and 46. In thisembodiment, the liquid return path 21 and evaporation channels 22 areformed from bent multiport tube structures 100 so as to obviate the needfor a turnaround manifold 24. That is, the multiport tube structures 100include a bend where the lower end of the liquid return path 21communicates with the evaporation channels 22. In some cases, any web107 may be removed from the liquid return path section of the multiporttube structure 100, e.g., to reduce heat transfer. Note in FIG. 46 thatthe multiport tube structure 100 is bent so that the evaporator channelsection extends further into the manifold 3 than the liquid return pathsection. This helps ensure liquid flows into the liquid return path andnot the evaporation channels.

FIG. 47 shows another illustrative embodiment of a thermosiphon device10 that employs one or more flat multiport tube structures having asection with a plurality of adjacent flow channels and one or more flatwebs that extend away from the flow channels in a plane of the multiporttube structure. In this illustrative embodiment, each flat multiporttube structure 100 defines a set of evaporation channels 22 and a vaporsupply path 11, or a set of condensing channels 12 and a liquid returnpath 21. That is, each multiport tube structure 100 defines a portion ofa condenser section 1 and an evaporator section 2. Opposite ends of themultiport tube structures 100 are fluidly coupled to turnarounds 14 and24, so that vapor flowing upwardly in the vapor supply path 11 of one ormore multiport tube structures 100 can enter the turnaround 14 and intothe condensing channels 12 of one or more multiport tube structures 100,and so that liquid flowing downwardly in a liquid return path 21 canenter the turnaround 24 and into evaporation channels 22 of one or moremultiport tube structures 100. The multiport tube structures 100 mayhave a cross section like that in FIG. 38, 40, 42, 43, or others. Aflange 33 may provide a separation between the condenser and evaporatorsections 1, 2, e.g., so that warm air at the evaporator sections 2 iskept away from the condenser sections 1. Thermal transfer structure 13may be thermally coupled to portions of the multiport tube structures100 that define condensing channels 12, and thermal transfer structure23 may be thermally coupled to portions of the multiport tube structures100 that define evaporation channels 22. However, portions of themultiport tube structures 100 that define a liquid return path or vaporsupply path may be free of thermal transfer structure, and in someembodiments portions of a web 107 may be removed from these portions aswell to reduce heat transfer. While in this embodiment multiport tubestructures 100 that define evaporation channels 22/vapor supply path 11are interdigitated with multiport tube structures 100 that definecondensing channels 12/liquid return path 21, other arrangements arepossible, such as clustering multiport tube structures 100 that defineevaporation channels 22/vapor supply path 11, or that define condensingchannels 12/liquid return path 21 in groups of two or more.

FIG. 48 shows one technique for arranging thermal transfer structure 13,23 like that shown in FIG. 47. Thermal transfer structure 13 (or 23) maybe sandwiched between two adjacent multiport tube structures 100, e.g.,squeezed in physical contact between webs 107 or other portions of themultiport tube structures 100. The thermal transfer structure 13 mayinclude a cladded side 13 a and a non-cladded side 13 b so that during abrazing, soldering or other similar process, the cladded side 13 a isbonded to the adjacent multiport tube structure 100 but the non-claddedside 13 b is not bonded to the adjacent multiport tube structure 100. Asa result, the thermal transfer structure 13 may better transfer heatwith the multiport tube structure 100 on the cladded side 13 a than onthe non-cladded side 13 b.

FIG. 49 shows another thermosiphon device 10 that is arranged similarlyto that in FIG. 47, but the upper turnaround 14 is omitted. In itsplace, the multiport tube structures 100 are bent to provide aturnaround 14 that fluidly connects a vapor supply path section 11 ofeach multiport tube structure 100 with a condensing channel 21 sectionof the structure 100. FIG. 50 shows yet another embodiment similar tothe FIG. 49 embodiment but with the lower turnaround 24 removed.Instead, the multiport tube structures 100 are bent to provideturnarounds 24 for each section that defines a liquid return path and asection that defines a set of evaporation channels. Since flow in thisarrangement will follow a closed loop, a manifold 3 is provided so thatliquid returned in the final liquid return path 21 at the extreme rightin FIG. 49 can return to the manifold 3 and enter the evaporationchannels 22 of the multiport tube structure 100 at the extreme left inFIG. 49. A fill tube 38 is provided to allow the device 10 to be filledwith working fluid in liquid form prior to being put into service.

FIG. 51 shows another embodiment of a thermosiphon device 10 thatincludes a multiport tube structure 100 in an evaporator or condensersection. In this embodiment, the condenser section 1 includes aplurality of multiport tube structures 100 that each defines a set ofcondensing channels 12 and includes webs 107 extending upwardly anddownwardly in the plane of the multiport tube structure 100. Thecondensing channels 12 are provided with working fluid vapor by a vaporsupply path 11 that leads from a set of evaporation channels 22 of theevaporation section 2. As can be seen in FIG. 52, since one end of thecondensing channels 12 is positioned higher than the opposite end,condensed working fluid flows into a liquid return path 21 and then tothe evaporation channels 22. All of the liquid return path 21, theevaporation channels 22 and the vapor supply path 11 may be formed froma multiport tube structure 100 which may or may not have a web 107. Asshown in FIG. 53, sections of web 107 may be provided for the vaporsupply path 11 and the liquid return path 21 so as to define aninsertion depth of the tube ends into a respective manifold 3. As can beseen in FIG. 51, manifolds 3 may be employed to fluidly couple the vaporsupply path 11 and the liquid return path 21 to the condensing channels12. FIG. 54 shows a manifold 3 which may include an opening 331 tocouple with the section of the multiport tube structure 100 definingcondensing channels 12 and an opening 332 to couple with the vaporsupply path 11 or the liquid return path 21. The manifolds 3 are neededin this embodiment because the multiport tube structures 100 that definethe condensing channels 12 may have a size and/or number of flowchannels that is different from the size and/or number of flow channelsin the multiport tube structure 100 that defines the liquid return path21, the evaporation channels 22 and the vapor supply path 11. FIG. 55shows an end view of a multiport tube structure 100 having a sectionthat defines a plurality of flow channels for the condensing channels 12and webs 107 extending outwardly from the section in the plane of themultiport tube structure 100. Of course, other numbers of flow channelsmay be employed. FIG. 56 shows a base plate 25 that may be used with thethermosiphon device 10. In this embodiment, the base plate 25 includes aplurality of grooves 251 that may each receive a set of evaporationchannels 22, e.g., which may be welded or otherwise bonded in place tothermally couple the channels 22 with the base plate 25. The base plate25 may itself be coupled with a heat source, such as one or more heatgenerating devices and transfer heat to the evaporation channels 22.

FIG. 57 shows an illustrative embodiment of a thermosiphon device 10similar to that in FIG. 51, except that the device 10 is shown orientedin a more vertical direction than the FIG. 51 embodiment. Similar to theFIG. 51 embodiment, the FIG. 57 embodiment includes a multiport tubestructure 100 that defines a plurality of condensing channels 12 andwhich may have a cross section like that in FIG. 38, 40, 42, 43, orothers. Like the FIG. 51 embodiment, all of the liquid return path 21,the evaporation channels 22 and the vapor supply path 11 may be formedfrom a multiport tube structure 100 which may or may not have a web 107.As shown in FIG. 58, multiple ones of the thermosiphon devices 10 inFIG. 57 may be ganged together into a single thermosiphon device 10, andas can be seen in FIG. 59, the liquid return paths 21 and evaporationchannels 22 may be coupled to a common turnaround 24, which may be atubular manifold. Alternately, or in addition, the manifolds 3 thatcouple the condensing channels 12 to the vapor supply path 11 and/or theliquid return path 21 may be coupled together by a common manifold 130as seen in FIG. 59A. Such an arrangement may help balance liquid andvapor flow amongst the parallel units.

FIG. 60 shows another illustrative embodiment of a thermosiphon device10 that includes a condenser section 1 that operates in acounterflow-type operation (like that in the device 10 of FIG. 36).However, somewhat differently from FIG. 36, the condenser channels 12 ofeach flat multiport tube structure 100 are fluidly coupled by a manifold3 at a bottom end and a turnaround 14 at a top end. The multiport tubestructures 100 may or may not have a web 107. Also in this embodiment,the evaporator section includes evaporator channels 22 and liquid supplypaths 21 that are provided by a plurality of multiport tube structures100 that may have a cross section like that in FIG. 31. Thus, sectionsof the multiport tube structures 100 that define the evaporationchannels 22 may be joined to sections that define the liquid return path21 by a web 103. Outer webs 107 and other features may be provided ornot.

In another aspect of the invention, a thermosiphon device may include atleast one multiport tube structure that defines at least one evaporationchannel and at least one condensing channel. The at least one condensingchannel may be joined to the at least one evaporation channel by a webthat extends between the at least one condensing channel and the atleast one evaporation channel in a plane of the multiport tubestructure. For example, FIG. 61 shows a thermosiphon device 10 thatincludes a plurality of multiport tube structures 100 that each includesa plurality of evaporation channels 22 (defined by a first section 101)and a plurality of condensing channels 12 (defined by a second section102) joined by a web 103. An outer web 107 is also provided in thisembodiment that extends outwardly from the second section 102 in a planeof the multiport tube structure 100. Ends of the first and secondsections 101, 102 are fluidly coupled to a respective manifold 3. Inthis embodiment, five multiport tube structures 100 are shown, but moreor fewer multiport tube structures 100 could be used. Upper and lowermanifolds 3 on opposite sides of the device 10 are fluidly coupled byconduits 37, which may be formed as a multiport tube structure 100,e.g., having a cross section like that in FIG. 38. As described above,the use of a multiport tube structure 100 for a conduit 37 may helpdefine an insertion depth into the manifolds 3 easier. The first section101 of each multiport tube structure 100 may be thermally coupled to abase plate 25, e.g., so as to receive heat from the base plate 25. Aswill be understood, working fluid liquid that is evaporated in theevaporation channel 22 may flow to a lower manifold 3, then flowupwardly through a conduit 37, into an upper manifold 3 and into acondensing channel 21. Condensed working fluid liquid may flow in anopposite direction. The device 10 may be relatively tolerant of tiltingor rotation in different directions, i.e., the device 10 may continue tooperate properly even when tilted or rotated to limited degrees aboutvarious axes parallel to the plane of the base plate 25. This may makethe device 10 suitable for a variety of applications or in applicationswhere the device 10 moves in different directions, such as on anairplane.

FIG. 62 shows the device 10 with the manifolds 3 and conduits 37 removedfor clarity. As can be seen in FIG. 62 and in FIG. 63, the multiporttube structures 100 may have a cross section in which the web 103 isrelatively wide and in which the first section 101 (defining theevaporation channels 22) has fewer flow channels than the second section102 (defining the condensing channels 12). Of course, other arrangementsare possible, including more and few flow channels for either section101, 102, a web 103 with different dimensions (width, thickness, length)or material, a web 103 with gaps or removed sections, etc. Also, the web103 and/or web 107 may help define an insertion depth for the first andsecond sections 101, 102 into a respective manifold 3, as discussedabove.

FIG. 64 shows another embodiment of a thermosiphon device 10 that issimilar to that in FIG. 61 except that the first and second sections101, 102 of each multiport tube structure 100 are fluidly coupled by apair of manifolds 3 and the multiport tube structures 100 are notfluidly coupled together. Another difference is that the cross sectionof the multiport tube structures 100 is different, as can be seen inFIG. 65. In this example, the web 103 is relatively narrow, and both thefirst and second sections 101, 102 (defining the evaporation channels 22and condensing channels 12, respectively) have more flow channels. Themanifolds 3 may have slot-like openings to respectively receive thefirst and second sections 101, 102, and the web 103 may define aninsertion depth for both sections 101, 102 in to the manifold. Incontrast to the FIG. 61 embodiment, the FIG. 64 embodiment may be moretolerant of rotation of the device about axes that extend along a lengthof the multiport tube structures 100. This is because working fluidcannot flow from one multiport tube structure 100 to another.

In accordance with another aspect of the invention, a thermosiphon mayinclude a condenser section with a plurality of sets of condensingchannels arranged to operate in a counterflow mode. That is, thecondensing channels may receive vaporized working fluid at a bottom end,conduct a flow of vapor upwardly in the channels, transfer heat fromevaporated liquid to a surrounding environment to condense the vapor toform a liquid, and conduct the flow of condensed liquid back to thebottom end of the channels. At least two of the plurality of sets ofcondensing channels may be part of a flat multiport tube structure inwhich the one set of condensing channels is joined to the another set ofcondensing channels by a flat web that extends between the sets ofcondensing channels in a plane of the multiport tube structure. Forexample, FIG. 66 shows a thermosiphon device 10 that includes aplurality of sets of condensing channels 12 that are fluidly coupled ata bottom end to a manifold 3. The manifold 3 may be thermally coupled toa base plate 25, e.g., to receive heat to vaporize working fluid liquidin the manifold 3. The vapor then enters the condensing channels 12, iscondensed, and returns to the manifold 3.

This embodiment includes multiport tube structures 100 that each havethree sets of condensing channels 12 (defined by first, second and thirdsections each with multiple flow channels), as can be seen in FIG. 67.The sets of condensing channels 12 are joined to an adjacent set by aweb 103 that extends in a plane of the multiport tube structure 100. Theweb 103 can not only aid in heat transfer, but also define an insertiondepth of a bottom end of the condensing channels 12 into the manifold 3and assist in simplifying manufacture of the device 10, e.g., byallowing three condensing channel sets to be mated with the manifold atone time. The upper end of the condensing channels 12 may be closed bycrimping, a cap, or other arrangement.

While the embodiment in FIG. 66 is shown operating in a horizontalposition, the device 10 may operate in other orientations, includingorientations in which the device 10 is rotated about an axis parallel tothe length of the multiport tube structures 100. For example, FIG. 68shows the manifold 3 oriented in a vertical position, e.g., in which thebase plate 25 is oriented vertically. The manifold 3 includes bends 301that are arranged to form a trap 302 that prevents each manifold segment3 engaged with a multiport tube structure 100 from completely drainingof working fluid liquid. As a result, the device 10 can continue tooperate properly even when tilted up to 90 degrees relative to thehorizontal about an axis parallel to the length of the multiport tubestructures 100. While the FIG. 66 embodiment includes bends 301 arrangedto form a trap 302, trapping liquid in manifold sections can be achievedin other ways. For example, FIG. 69 shows U-bends 301 in a manifold 3that have a plug 303 positioned at one end of each bend 301. The plug303 has an opening at one side so that the plug 303 functions to trapliquid in the manifold section up to the level of the opening in theplug. 303.

While the FIG. 66 embodiment shows the condenser channel sets extendingupwardly generally perpendicularly to the base plate 25, otherarrangements are possible. For example, FIG. 70 shows a modification ofthe FIG. 66 embodiment in which the condensing channels 12 are arrangedat an angle 9 relative to the vertical with the base plate 25 arrangedhorizontally. This arrangement allows the device 10 to operate in thehorizontal orientation shown in FIG. 70, and a vertical orientationshown in FIG. 71 in which the base plate 25 is vertical, and other tiltangles between the horizontal and vertical. That is, the inclinationangle of the condensing channels 12 ensures that the condensing channels12 drain condensed liquid even when the device 10 is in the verticalposition. Accordingly, the FIG. 70 arrangement is adapted for a varietyof different orientations. Note that FIG. 72 shows a perspective view ofthe base plate 25 having grooves 251 to receive manifold sections 3which may be thermally coupled to the base plate 25. The base plate 25is not required, and can be omitted, or can be altered in size, shapeand/or material. If the base plate 25 is omitted, the orientation of thedevice 10 may be referenced based on a plane of the manifold 3, e.g., aplane that passes through manifold sections engaged with condensingchannel sets.

FIG. 73 shows another thermosiphon device 10 that can be operated in avariety of different orientations. This embodiment also includes aplurality of multiport tube structures 100 that each includes four setsof condensing channels 12 that are fluidly coupled at a bottom end to amanifold 3. A perspective view of a multiport tube structure 100 isshown in FIG. 74. The manifold 3 in this embodiment (see FIG. 75)includes a sheet with convex features having openings 331 to receive acondensing channel section of the multiport tube structure 100. Themanifold sheet 3 is coupled to a base plate 25, which has channels 251that correspond to the convex features. Together the sheet and the baseplate 25 form a manifold with flow channels for working fluid. The FIG.73 embodiment can operate in a horizontal orientation shown in FIG. 73,as well as a vertical orientation shown in FIG. 76. The device 10operates in this orientation, in part, because the channels 251 areshaped and cooperate with the manifold sheet 3 so as to provide a cavity252 adjacent the end of each condensing channel set to receive and holdliquid working fluid. (Without the cavities 252, the condensing channels12 might flood with liquid, decreasing their effectiveness.) The device10 can even operate when flipped over in a vertical orientation shown inFIG. 77. Again, the channels 251 are shaped and cooperate with themanifold sheet 3 to define a cavity 253 to receive and hold liquid,allowing the device to operate. While in these embodiments, thecondensing channels 12 extend generally perpendicularly relative to thebase plate 25, the condensing channel sets may extend at other anglesrelative to the plane of the base plate 25. Also, the base plate 25 maybe arranged in other ways, e.g., as shown in FIGS. 78 and 79. In thisembodiment, the base plate 25 is formed from a sheet that is bent toform the channels 251 and other structure of the base plate 25. FIG. 80shows another modification in which the base plate 25 includes a singlecavity 251 that spans multiple convex features of the manifold sheet 3.To aid in desirably moving liquid working fluid in the cavity 251, awicking element 255 is provided, e.g., to help distribute fluid bywicking and/or to increase a surface area of the working fluid andenhance boiling.

FIG. 81 shows a thermosiphon device 10 that is similar to that in FIG.66 with the major difference being that the manifold sections 3 arefluidly coupled by conduits 304 rather than bends 301. A close up viewof the conduits 304 is shown in FIG. 82, and the conduits 304 may bearranged as shown in FIG. 83, e.g., as a multiport tube structure 100with a first section 101 defining one or more flow channels and a pairof webs 107 extending outwardly from the first section 101. The webs 107may help define an insertion depth of the conduits 304 into the manifoldsections 3. FIG. 84 shows a close up view of a conduit 304 and how thewebs 107 define an insertion depth D into a manifold section 3. Thisinsertion depth D may help trap working fluid liquid in manifoldsections 3 when the device is tilted, e.g., to a vertical position asshown in FIG. 84, thereby helping keep the device 10 in efficientoperation even in a tilted orientation.

FIG. 85 shows another arrangement to help trap liquid in a manifold 3.In this embodiment, the inner wall of the manifold 3 includes aninternal thread feature 307 that helps trap liquid in the manifold 3,e.g., in the thread grooves. Thus, the thread feature 307 may help keepa manifold section from completely draining, thereby making workingfluid liquid available for evaporation and heat transfer. In anotherillustrative embodiment, the internal thread feature 307 may be providedby a coil element, such as that shown in FIG. 86, rather than a threadgroove formed in the inner wall of the manifold 3. The coil element maybe brazed or otherwise secured in place, or held by friction orinterference fit in the manifold 3. A brazed, adhered or other similarconnection may aid in preventing liquid flow in any space between thecoil element and the inner wall of the manifold 3. The additionalsurface area of the thread or coil feature exposed to the liquid mayenhance heat transfer.

FIG. 87 shows another thermosiphon device 10 that is similar inoperation to the FIG. 66 embodiment in that a plurality of condensingchannel sets operate in a counterflow mode. However, in this embodiment,the manifold 3 has a circular tube, and the condensing channels arearranged in a multiport tube structure like that shown in FIG. 38. Also,the manifold 3 includes a plurality of plugs 303 that help trap workingfluid liquid in desired areas of the manifold 3, e.g., at or near thecondensing channels 12 of each multiport tube structure 100. FIG. 88shows the manifold 3 alone with plugs 303 positioned between eachopening 331 to receive a corresponding manifold end of a multiport tubestructure 100. FIG. 89 shows a plug 303 with an opening 303 a. The plug303 is positioned in the manifold 3 so that the opening 303 a ispositioned to control a depth of liquid in the manifold in adjacentsections. In an alternative embodiment shown in FIG. 90, the plugs 303may be replaced with a wicking element 255 that functions to encourageflow of liquid in the manifold 3.

FIG. 91 shows another illustrative embodiment of a thermosiphon device10 that operates similarly to that in FIG. 87, except that the circularmanifold 3 is replaced with a manifold 3 having a cylindrical chambershape. As can be seen in FIG. 92, the manifold 3 may include a wickingelement 255 to encourage and spread flow of the liquid working fluid inthe manifold 3. Alternately, as shown in FIG. 93, the manifold 3 mayinclude a plurality of cavities 306 at a bottom of the manifold 3 tohold working fluid liquid. The cavities 306 may increase a surface areaexposed to the liquid, thereby enhancing heat transfer. The workingfluid liquid level in the manifold 3 may be maintained above a top levelof the cavities 306 to ensure that the cavities 306 are all filled withliquid.

FIG. 94 shows yet another embodiment of a thermosiphon device 10 thatincludes a plurality of multiport tube structures with sections todefine sets of condensing channels 12. In this case, each multiport tubestructure 100 has three sections that define condensing channels 12, andadjacent sections are joined by a web 103. The manifold 3 is arranged asa bent tube and includes one or more plugs 303 with openings 303 apositioned to trap liquid in desired sections of the manifold at adesired level. As in other embodiments, the manifold 3 has openings toreceive a manifold end of each condenser channel set, and the webs 107and/or 103 may help define an insertion depth of the manifold ends intothe manifold. Plugs 303 may be positioned in the manifold 3 between eachcondensing channel set, and may be arranged to trap liquid so that thedevice 10 can operate properly even when tilted through a wide varietyof angles and in a wide variety of directions. In fact, the device 10may operate in a vertical orientation as shown in FIG. 94, at ahorizontal orientation shown in FIG. 95, or other orientations inbetween.

The embodiments provided herein are not intended to be exhaustive or tolimit the invention to a precise form disclosed, and many modificationsand variations are possible in light of the above teachings. Theembodiments were chosen and described in order to best explain theprinciples of the invention and its practical application to therebyenable others skilled in the art to best utilize the invention invarious embodiments and with various modifications as are suited to theparticular use contemplated. Although the above description containsmany specifications, these should not be construed as limitations on thescope of the invention, but rather as an exemplification of alternativeembodiments thereof.

The indefinite articles “a” and “an,” as used herein in thespecification and in the claims, unless clearly indicated to thecontrary, should be understood to mean “at least one.”

The phrase “and/or,” as used herein in the specification and in theclaims, should be understood to mean “either or both” of the elements soconjoined, i.e., elements that are conjunctively present in some casesand disjunctively present in other cases. Multiple elements listed with“and/or” should be construed in the same fashion, i.e., “one or more” ofthe elements so conjoined. Other elements may optionally be presentother than the elements specifically identified by the “and/or” clause,whether related or unrelated to those elements specifically identified.

The use of “including,” “comprising,” “having,” “containing,”“involving,” and/or variations thereof herein, is meant to encompass theitems listed thereafter and equivalents thereof as well as additionalitems.

It should also be understood that, unless clearly indicated to thecontrary, in any methods claimed herein that include more than one stepor act, the order of the steps or acts of the method is not necessarilylimited to the order in which the steps or acts of the method arerecited.

While aspects of the invention have been described with reference tovarious illustrative embodiments, such aspects are not limited to theembodiments described. Thus, it is evident that many alternatives,modifications, and variations of the embodiments described will beapparent to those skilled in the art. Accordingly, embodiments as setforth herein are intended to be illustrative, not limiting. Variouschanges may be made without departing from the spirit of aspects of theinvention.

1.-45. (canceled)
 46. A thermosiphon cooling device including: acondenser section including a plurality of sets of condensing channelsarranged to operate in a counterflow mode to transfer heat fromevaporated liquid to a surrounding environment to condense theevaporated liquid; and at least one conduit fluidly connected to theplurality of sets of condensing channels arranged to provide workingfluid vapor to the plurality of sets of condensing channels and toreceive condensed working fluid liquid from the plurality of sets ofcondensing channels, wherein at least one of the plurality of sets ofcondensing channels is part of a flat multiport tube structure that hasa web that extends from a set of condensing channels in a plane of themultiport tube structure.
 47. The device of claim 46, further comprisingan evaporator section including at least one evaporation channelarranged to receive heat and evaporate a liquid in the at least oneevaporation channel.
 48. The device of claim 47, further comprising aliquid return path for delivering condensed liquid to the at least oneevaporation channel.
 49. The device of claim 48, wherein the liquidreturn path and the at least one evaporation channel are fluidly coupledto the at least one conduit.
 50. The device of claim 49, wherein the atleast one evaporator section includes a multiport tube structure havinga first portion defining a plurality of evaporation channels andincluding a web that extends from the first portion in a plane of themultiport tube structure.
 51. The device of claim 50, wherein the webextends between the first section and a second section of the multiporttube structure that defines the liquid return path.
 52. The device ofclaim 46, wherein at least two of the plurality of sets of condensingchannels are part of a flat multiport tube structure in which the oneset of condensing channels is joined to the another set of condensingchannels by a flat web that extends between the sets of condensingchannels in a plane of the multiport tube structure.
 53. The device ofclaim 52, wherein at least three of the plurality of sets of condensingchannels are part of a flat multiport tube structure in which adjacentpairs of the sets of condensing channels are joined by a flat web thatextends between the sets of condensing channels.
 54. The device of claim46, wherein the at least one conduit includes multiple manifold sectionsthat are fluidly coupled together, each manifold section being fluidlycoupled to a corresponding set of condensing channels.
 55. The device ofclaim 54, further comprising a trap or plug between manifold sections toresist liquid flow from one manifold section to another manifoldsection.
 56. The device of claim 46, wherein adjacent manifold sectionsare fluidly coupled by a conduit having a flat tube section and websextending outwardly from opposite ends of the flat tube section.
 57. Thedevice of claim 46, wherein the plurality of sets of condensing channelsare arranged at an angle between 0 and 90 degrees relative to a plane ofthe at least one conduit.
 58. The device of claim 46, wherein the atleast one conduit includes a base plate having a plurality of channelsand a sheet that is attached to the base plate so as to close theplurality of channels.
 59. The device of claim 58, wherein the channelsand the sheet are formed to define cavities adjacent a set of condensingchannels with the device oriented in a vertical orientation.
 60. Thedevice of claim 46, wherein at least one of the plurality of sets ofcondensing channels is part of a flat multiport tube structure that hasa first section defining a plurality of condensing channels and firstand second flat webs that extend away from the first section in a planeof the multiport tube structure on opposite sides of the first section.61. The device of claim 60, wherein the at least one conduit includes acylindrical chamber having a top with an opening to receive a manifoldend of the first section of the flat multiport tube structure.
 62. Thedevice of claim 61, further comprising a plurality of flat multiporttube structures arranged vertically and having a manifold end of thefirst section engaged with an opening at the top of the cylindricalchamber.
 63. The device of claim 46, wherein the at least one conduitincludes a tubular manifold having an opening to receive a manifold endof the first section of the flat multiport tube structure.
 64. Athermosiphon cooling device including: an evaporator section includingat least one evaporation channel arranged to receive heat and evaporatea liquid in the at least one evaporation channel and a liquid returnpath for delivering condensed liquid to the at least one evaporationchannel; a condenser section including at least first and second sets ofcondensing channels arranged to transfer heat from evaporated liquid toa surrounding environment to condense the evaporated liquid, and a vaporsupply path for delivering evaporated liquid to the at least onecondensing channel; and a manifold fluidly connecting the evaporatorsection and the condenser section, wherein the manifold includes firstand second liquid chambers that are fluidly coupled to the first andsecond sets of condensing channels, respectively, and a vapor chamberfluidly coupled to the vapor supply path, and wherein the manifoldincludes an end cap that fluidly couples the first and second liquidchambers.
 65. The device of claim 64, wherein the first liquid chamberis fluidly coupled to the liquid return path.
 66. The device of claim64, wherein the condenser section is formed as a flat multiport tubestructure that includes the first and second sets of condensing channelspositioned on opposite sides of at least one vapor supply channel thatdefines the vapor supply path, wherein the first and second sets ofcondensing channels are each connected to the at least one vapor supplychannel by a respective connecting web.
 67. The device of claim 66,wherein the manifold includes an outer wall with first, second and thirdopenings, wherein the first set of condensing channels is received inthe first opening, the second set of condensing channels is receivedinto the second opening and the at least one vapor supply channel isreceived into the third opening.
 68. The device of claim 66, wherein thecondenser section includes a plurality of flat multiport tube structuresthat each include the first and second sets of condensing channelspositioned on opposite sides of at least one vapor supply channel. 69.The device of claim 64, wherein the end cap includes an inner plate witha first opening in fluid communication with the first liquid chamber anda second opening in fluid communication with the second liquid chamber,and an outer plate to sealingly close the manifold, wherein the innerand outer plates are offset to define a chamber that fluidly couples thefirst and second openings.
 70. The device of claim 69, furthercomprising first and second separation plates in the manifold thatseparate an internal space of the manifold into the first and secondliquid chambers and the vapor chamber, wherein ends of the first andsecond separation plates are in sealing engagement with the inner plate.